Hydraulic accumulator, especially bladder accumulator

ABSTRACT

The invention relates to a hydraulic accumulator, especially a bladder accumulator, comprising an accumulator housing ( 10 ), a separation element disposed therein that separates within the accumulator housing a gas chamber ( 16 ) adjoining an inlet ( 14 ) on the gas side from a fluid chamber ( 18 ) adjoining an inlet ( 20 ) on the fluid side. Said inlet on the fluid side has a fluid connecting neck ( 22 ) which comprises a valve support ( 40 ) disposed in said neck and having fluid openings ( 42 ), and a disk-shaped valve body ( 32 ) that tapers towards the valve shaft ( 46 ) on its side facing the valve support ( 40 ). Said valve shaft can be pretensioned via a force accumulator ( 62 ) into the open position in which it releases the fluid opening, and can be displaced into its closed position by a displacement of the separation element ( 12 ), and projects into the fluid chamber ( 18 ) in the open position. The valve body ( 32 ) is an integral, especially one-piece component of the valve support ( 40 ) that is guided along its outer periphery ( 56 ) within the connecting neck ( 22 ) so as to be displaceable therein, thereby creating a hydraulic accumulator that is comparatively simple and inexpensive in production.

[0001] The invention relates to a hydraulic accumulator, especially a bladder accumulator, with an accumulator housing, a separating element which is located therein and which separates in the accumulator housing a gas chamber which borders a gas-side access from a fluid chamber which borders the fluid-side access which has a fluid connecting piece, and with a valve support which is located on the connecting piece with fluid passages, and with a plate-like valve body which tapers toward the valve shaft on its side facing the valve support and which is pretensioned into its open position which clears the fluid passage by way of an energy accumulator, and can be moved into its closed position by the motion of the separating element, and which projects in the indicated open position into the fluid chamber.

[0002] Hydraulic accumulators of this type are commercially available. In the technical reference published by Mannesmann Rexroth GmbH “Der Hydrauliktrainer” [Hydraulic Training Manual], Volume 1 on page 165, a bladder accumulator of the aforementioned type is described. In the disclosed bladder accumulator the valve arrangement is made as a seat valve, on the end edge of the connecting piece facing the fluid chamber, as the stationary valve seat, a conical surface being formed which interacts with the corresponding conical surface on the valve plate of the movable valve body. It is made similarly to the control valves which are conventional in valve-controlled internal combustion engines, i.e., the valve plate is located on a shaft which is guided in a valve guide as the valve support for the valve lifting motion which runs between the open position and closed position, and the valve guide is a component of the connecting piece.

[0003] The disadvantage here is the resulting high production costs due to the required expenditures for producing and machining of a plurality of individual parts as a result of this valve design. In order to ensure proper operation of the valve arrangement, the valve guide installed in the connecting piece must be made carefully with respect to production tolerances, both with regard to alignment and fit. Moreover, the corresponding machining of the conical surfaces which form the valve seat is necessary. This likewise increases production costs, such as the fact that at least the valve plate of the valve body is produced by forging.

[0004] DE-A-199 06 800 discloses a hydraulic accumulator with a housing with an interior divided by a media separating element into two chambers, the first chamber being filled with a gas and the second chamber being filled with a liquid, and in the hydraulic connection there being a bottom valve with a closing body which can be actuated by the media separation element in the form of the actuating plate of a spring bellows and it enables the second chamber to be filled with liquid and prevents the second chamber from being completely evacuated.

[0005] In order to both prevent damage of the bottom valve and also unintentional emergence of liquid and thus to ensure a considerable increase of operating reliability, in the known approach it is proposed that the closing body can be moved by the media separating element into a position in which the function of a hydraulic piston is performed. The closing body on its side facing the separating plate of the spring bellows accumulator has a spherical actuating part so that in this respect application of force with spot force peaks takes place by way of the media separating element on the closing body. The known valve body which is completely guided in the connecting piece moreover requires for its sealing relative to the connecting piece on the outer periphery side rubber-elastic sealing means which are basically subject to wear so that they must be replaced by new ones from time to time in order to ensure the operating reliability of the hydraulic accumulator.

[0006] On the basis of this state of the art the object of the invention is to develop a hydraulic accumulator which can be produced comparatively more easily and economically with simultaneously increased operating reliability and longer maintenance intervals.

[0007] In a hydraulic accumulator of the indicated type, this object is achieved as claimed in the invention in that the valve body is a one-piece component of the valve support which is guided to move lengthwise along its outside periphery within the connecting piece in the latter. By eliminating a separate valve structure which is to be installed in the connecting piece, the cost for production, machining and assembly is greatly reduced. With the approach as claimed in the invention it is possible to make the valve body as a component of the valve support in the manner of an insertion module and the pertinent module components can be quickly and easily inserted into the fluid connecting piece and can be fixed to be able to move lengthwise there. With respect to the modular structure, in the manner of a module, adaptations to altered size ratios, especially with respect to the connecting piece, for the hydraulic accumulator can be quickly and easily done. Since the valve support is guided on the outer periphery side along the inside circumference of the connecting piece, the guide surface can be enlarged such that secure, fitted guidance can be achieved; this increases the operating reliability of the approach as claimed in the invention. Furthermore the sealing system which is subject to wear can be completely abandoned.

[0008] Based on the plate-like embodiment of the valve body, flat contact of the indicated separating element takes place so that in this respect flat actuation takes place carefully; this likewise helps to reduce wear and consequently benefits the operating reliability of the hydraulic accumulator approach as claimed in the invention.

[0009] In one preferred embodiment of the hydraulic accumulator as claimed in the invention, the fluid passages in the valve support are located diametrically to its lengthwise axis and to the lengthwise axis of the valve body opposite one another. In this way the required number of fluid passages can be easily and economically provided in the valve support.

[0010] If by preference the energy accumulator in the form of a compression spring is supported with its one end on the connecting piece and with its other end on the valve support, this supports the modular structure of the approach and the compression spring can be easily and economically inserted into the connecting piece. Preferably it is provided that in the maximum possible open position of the valve body the valve support strikes a stop in the connecting piece, and that in the completely closed position of the valve body it is at least with its plate edge in contact with the connecting piece.

[0011] If in one preferred embodiment of the hydraulic accumulator as claimed in the invention the stop is formed by a sealing ring which fits into a recess on the inside periphery of the connecting piece, the sealing ring can be reliably inserted by way of a mounting groove on the outside periphery of the valve support into the recess on the connecting piece, so that with a simple catch process against the action of the compression spring in only one process the insertion module can be completely installed. The path between the stop and the end-sided outlet of the mounting groove is made especially larger than the free path of travel of the valve body from the maximum possible open position to its completely closed position in order to later achieve unhindered operation of the valve body with the valve support and to enable installation.

[0012] If by preference the valve body with the valve support is designed to be machined as a turned part, the valve means as claimed in the invention can be implemented from a rod-shaped base material by means of conventional automatic lathes in an especially economical manner, the forging processes ordinarily used to date entailing a distinct cost increase for the valve plate. Preferably it is furthermore provided that the fluid passages be economically implemented in a valve support in the form of individual holes.

[0013] The hydraulic accumulator as claimed in the invention is detailed below using one embodiment as shown in the drawings which are in outline form and are not drawn to scale.

[0014]FIG. 1 shows partially in a view, partially in a lengthwise section, a known hydraulic accumulator in the form of a bladder accumulator;

[0015]FIG. 2 shows in a perspective a section through the valve means as claimed in the invention with a connecting piece;

[0016]FIG. 3 shows a corresponding lengthwise section according to the arrangement as shown in FIG. 2.

[0017]FIG. 1 shows a conventional bladder accumulator which can be found in the prior art, with an accumulator housing 10 which is made as a pressurized housing. In the accumulator housing 10 is an elastically flexible separating element 12 which separates the gas chamber 16 which borders the gas-side access 14 from the fluid chamber 18 which borders the fluid-side access 20. The indicated fluid-side access 20 has a fluid connecting piece 22 which is made in the manner of a hollow cylinder. Viewed in the line of sight to FIG. 1, the connecting piece 22 on its lower inner side has a connecting point 24 with internal threads to which a fluid line can be connected. On its opposite end the connecting piece 22 has a widened area 26 which on the inner peripheral side is provided with a contact bevel 28 for contact of the lower plate edge 30 of the valve body 32 in its closed position (not shown). To fix the fluid connecting piece 22 on the lower open end of the accumulator housing 10 there are fixing rings 34 which are located on the one hand within the accumulator housing 10 and according to FIG. 1, on the other hand, outside. For bracing of the fixing rings 34 against one another for purposes of fixing the connecting piece 22 on the lower edge of the accumulator housing there is a lock nut 36 which can be screwed onto the outside thread 38 of the connecting piece 22.

[0018] In the middle of the connecting piece 22 in the area of the fluid-carrying part of the hydraulic accumulator there is a valve support 40 with fluid passages 42 which are diametrically opposite one another. The pertinent fluid passages 42 join the connecting point 24 to the fluid chamber 18 of the hydraulic accumulator, carrying fluid. The valve support 40 along the middle lengthwise axis 44 is provided with a central hole through which the valve shaft 46 of the plate-like valve body 32 extends, as shown in FIG. 1 the free end of the valve shaft 46 being provided with a screw connection 48. Between the lower end of the actual valve plate 50 of the valve body 32 and the top contact surface of the valve support 40, an energy accumulator in the form of a compression spring 52 extends. The pertinent energy accumulator 52 tensions the valve body 32 according to FIG. 1 into its open position which clears the fluid passage and by the motion of the separating element 12 in the direction of the fluid-side access 20 the valve body 32 travels into its closed position in which the plate edge 30 of the valve body 32 makes sealing contact with the contact bevel 28 of the fluid connecting piece 22. Furthermore, a fluid-tight safeguard of the interior of the accumulator housing 10 relative to the environment in the area of the connecting piece 22 is achieved by way of sealing points 54 in a conventional manner which is not detailed.

[0019] The pertinent structure for a hydraulic accumulator is conventional and prior art. It becomes clear from what was described above that the production cost for the connecting piece 22 with an integrated valve support 40 and fixing the valve body 32 on the valve support 40 by way of a screw connection is considerable; this leads to high production costs. Furthermore, that at least the valve plate 50 of the valve body 32 is made as a forged part also contributes to high production costs. Conversely, with the approach as claimed in the invention as shown in FIGS. 2 and 3 a more economical implementation is achieved, for the explanation of the invention the same reference numbers as described above being used for the components to the extent they correspond to one another in terms of their function.

[0020] In the approach as claimed in the invention, the valve body 32 is an integral, especially a one-piece component of the valve support 40 which is guided to be able to move lengthwise along its outside periphery 56 within the connecting piece 22 in the latter. To guide the piston-like valve support 40 along the connecting piece 22 the two components have appropriately made cylindrical guide surfaces which allow uninhibited motion. The structural dimensions for the valve support 40 are such that the height corresponds comparably to its diameter, the dimensions selected in this way ensuring reliable and straight guidance. In the approach as claimed in the invention there are four fluid passages 42 (cf FIG. 2) in the valve support 40 diametrically to its lengthwise axis 44 and moreover to the lengthwise axis of the valve body 32 opposite one another. The indicated fluid passages 42 are bordered to the outside by the outside wall of the valve support 40, the remaining residual wall thickness, as the figures show, being made small. To the inside the fluid passages 42 are bordered by the valve shaft 46 which passes in one piece into the other body housing of the valve support 40.

[0021] In the approach as claimed in the invention the energy accumulator 52 in the form of a compression spring is located underneath the piston-like valve support 40, the compression spring being supported with its one lower end on the connecting piece 22 and with its other, opposing end on the valve support 40. For supporting the compression spring 52 on its lower end the connecting piece 22 has a contact shoulder 58 which projects to the inside and on its upper end the compression spring 52 is supported on the annular boundary wall 60 of the valve support 40 so that the four fluid passages 42 are kept free in the direction of the connecting point 24 for the fluid connection (not shown).

[0022] In the maximum possible open position of the valve body 32 shown in FIGS. 2 and 3, the valve support 40 strikes a stop 62 in the connecting piece 22 so that the path of motion of the valve support 40 is bordered to the top by this stop 62. In the completely closed position (not shown) of the valve body 32 its lower plate edge 30 adjoins the contact bevel 28 of the connecting piece 22. In this closed position the fluid passage from the fluid chamber 18 in the direction of the connecting point 24 by way of the fluid passage 42 in the form of longitudinal holes is blocked. The stop 62 is formed by a sealing ring 64 which is made in the manner of a conventional snap ring. In the installation situation the pertinent, annularly elastically flexible safety ring 64 fits into a semicircular recess 66 on the inside periphery 68 of the connecting piece 22.

[0023] To produce the pertinent connection the sealing ring 64 is inserted first by way of a mounting groove 70 which extends annularly along the outside periphery 72 of the valve support 40 into the latter outside the connecting piece 22. After inserting the compression spring 52 into the interior of the connecting piece 22 the valve support 40 with the valve body 32 and the sealing ring 64 can then be pushed into the connecting piece 22 against the action of the compression spring 52 until the mounting groove 70 with the sealing ring 64 at the height of the recess 66 reaches the inside periphery 68 of the connecting piece 22. Due to inherent elasticity, the sealing ring 64 then snaps to the outside into the recess 66 and thus captively forms the stop 62. In the pertinent installation position then the valve unit is fixed reliably within the connecting piece 22 and in the maximum possible open position presses the compression spring 52 of the valve support 40 against the stop 62 so that in this way the valve support 40 is held captively in the connecting piece 22. The free path between the stop 62 and the end-side run of the mounting groove 70 is however chosen to be larger that the free path of motion of the valve body 32 from the indicated maximum possible open position to its completely closed position, at which the plate edge 30 of the valve body 32 is in contact with the contact bevel 28 on the top free end of the connecting piece 22. As a result of the inherent elasticity of the sealing ring 64 there is moreover no danger that it could spring back into the mounting groove 70.

[0024] The valve support 40 with the valve body 32 and consequently with the valve plate 50 can be obtained as a so-called turned part by machining on conventional automatic lathes. The pertinent machining is extremely economical compared to the otherwise conventional production as a forging. The fluid passages 42 in the valve support 40 are implemented in the form of individual holes which are made in the valve support 40 on the opposing side of the valve plate 50. The sealing ring 64 can be removed conventionally by access via the fluid passages 42 from the recess 66 on the connecting piece 22 so that in this respect the valve unit as a modular component can be easily replaced by a new one if repair or the like should be necessary. The described approach as claimed in the invention can be economically produced and easily installed; this clearly reduces the production costs for hydraulic accumulators. The described use of the valve system unit as claimed in the invention is not limited to bladder accumulators as hydraulic accumulators, but can also be used for example in piston accumulators in which the separating element 12 is made from a separating piston (not shown). 

1. Hydraulic accumulator, especially bladder accumulator, with an accumulator housing (10), a separating element which is located therein and which separates in the accumulator housing a gas chamber (16) which borders a gas-side access (14) from a fluid chamber (18) which borders the fluid-side access (20) which has a fluid connecting piece (22), and with a valve support (40) which is located on the connecting piece (22) with fluid passages (42) and with a plate-like valve body (32) which tapers toward the valve shaft (46) on its side facing the valve support (40) and which is pretensioned into its open position which clears the fluid passage by way of an energy accumulator (52), and can be moved into its closed position by the motion of the separating element (12), and which projects in the indicated open position into the fluid chamber (18), characterized in that the valve body (32) is an integral, especially a one-piece component of the valve support (40) which is guided to be able to move lengthwise along its outside periphery (56) within the connecting piece (22) in the latter.
 2. The hydraulic accumulator as claimed in claim 1, wherein the fluid passages (42) in the valve support (40) are located diametrically to its lengthwise axis (44) and to the lengthwise axis (44) of the valve body (32) opposite one another.
 3. The hydraulic accumulator as claimed in claim 1 or 2, wherein the energy accumulator (52) in the form of a compression spring is supported with its one end on the connecting piece (22) and with its other end on the valve support (40).
 4. The hydraulic accumulator as claimed in one of claims 1 to 3, wherein in the maximum possible open position of the valve body (32) the valve support (40) strikes a stop (62) in the connecting piece (22), and wherein in the completely closed position of the valve body (32) it is at least with its plate edge (30) in contact with the connecting piece (22).
 5. The hydraulic accumulator as claimed in claim 4, wherein the stop (62) is formed by a sealing ring (64) which fits into a recess (66) on the inside periphery (68) of the connecting piece (22).
 6. The hydraulic accumulator as claimed in claim 5, wherein the sealing ring (64) can be inserted by way of a mounting groove (70) on the outside periphery (72) of the valve support (40) into the recess (66) on the connecting piece (22).
 7. The hydraulic accumulator as claimed in claim 6, wherein the path between the stop (62) and the end-sided run of the mounting groove (70) is larger than the free path of travel of the valve body (32) from the maximum possible open position to its completely closed position when the valve body (32) is installed in the connecting piece (22).
 8. The hydraulic accumulator as claimed in one of claims 1 to 7, wherein the valve body (52) with the valve support (40) is designed to be machined as a turned part.
 9. The hydraulic accumulator as claimed in claim 8, wherein the fluid passages (42) are implemented in a valve support (40) in the form of individual holes.
 10. The hydraulic accumulator as claimed in one of claims 1 to 9, wherein the fluid passages (42) are made in the form of lengthwise holes, said fluid passages (42) being bordered to the outside by the outside wall of the valve support (40) and to the inside by the valve shaft (46). 